Automatically add extra sitemaps to the sitemap-index.xml via options

[xenitane]

Body

Sumary

Ability to link extra sitemaps(probably from other projects) to the sitemap-index.xml. You can filter out pages and add custom pages but not link other sitemaps.

Background & Motivation

I recently worked on a static site in astro, great experience. Then I moved to my next project, which again was another static site. As these are different projects, they'll have their individual sitemaps, but I just wanted to refer the sitemap of the second project and of those that I'll create in future in the first's one.

Goals

Have a lightweight and non-breaking change that'll help in generation of custom sitemaps via an optional field in the options object of the sitemap.

Worries

There can be unintentional collisions in the URLs by doing so, where we can simply ignore the duplicates.

Example

Example of how the config might look like.

/** @type {import("astro/config").AstroUserConfig} */

import { defineConfig } from "astro/config";
import sitemap from "@astrojs/sitemap"

export defineConfig({
    integrations:[
        sitemap({
            extraSitemaps:[ /* all the extra sitemaps that we want to refer here */ ]
        })
    ]
})

current workaround

For now, I am making use of a bash script during the CI to achieve this but it will be super handy to have an option to do this within the config itself.

# sitemap urls
SITEMAP_URLS=("https://a.com/p1/sitemap-index.xml" "https://a.com/p2/sitemap-index.xml")

# sitemap index file
SITEMAP_FILE="./dist/sitemap-index.xml"

SITEMAP=$(cat $SITEMAP_FILE) # original sitemap

for URL in "${SITEMAP_URLS[@]}"; do # loop for adding the urls to the sitemap
    if ! echo $SITEMAP | grep -qs "$URL"; then
        SITEMAP=$(echo "$SITEMAP" | sed "s#</sitemapindex>#<sitemap><loc>$URL</loc></sitemap></sitemapindex>#")
    fi
done

# final version of sitemap
echo $SITEMAP >$SITEMAP_FILE

[neerajlovecyber]

same needed

[delucis]

Linking this PR that implements this for people to subscribe to or review:
withastro/astro#13682